1. Field of the Invention
The present invention relates to an IC chip having a pad layout of high versatility.
2. Description of the Related Art
In an IC device including an integrated circuit, pads of an IC chip and pins of an IC package are connected to each other by bonding in order to draw a bonding wire out of the IC chip. When this bonding wire straddles over a constituent element of the IC chip, or when the bonding wire intersects another bonding wire, malfunction of the IC device is caused. Therefore, it is necessary to design the IC device in consideration of these points. Accordingly, the pins of the IC package are arranged according to the configuration of the constituent elements of the IC chip, or the constituent elements of the IC chip are arranged according to the configuration of the pins in the IC package. Therefore, in a conventional IC device, one type of IC chip design approximately corresponds to one type of an IC package.
Therefore, when a plurality of IC packages respectively having different configurations of pins are required to mounted IC chips having the same circuit configuration, it is necessary to design and manufacture IC these chips with the same number of different circuit layouts as that of the pin configurations of the IC packages. For example, in order to produce six different pin configurations, six different circuit patterns are required to be formed on one wafer. The number of each circuit pattern obtained in this manner is only 1/6 of the number obtained by forming only one pattern on a wafer. When different numbers of the respective circuit patterns are desired, the yield is lowered. Or, when one circuit pattern is formed on one wafer, six different types of wafers must be produced. Thus, there were many problems in making an IC chip having plural kinds of circuit patterns.